Thunderbird install instead of IceDove on Trisquel8

Hello!

I have Icedove installed in my Trisquel8 system. But it seems:
- Icedove is not the latest one - 52.9.1 version from Trisquel8 repository seems to be over a year old? https://en.wikipedia.org/wiki/Mozilla_Thunderbird#Releases
I am worried for security updates - is our mail client patched for security?
- IceDove is no longer necessary, since licensing problem was apparently resolved with Thunderbird:
https://en.wikipedia.org/wiki/Mozilla_software_rebranded_by_Debian#Icedove

But when I try simply

sudo apt-get install thunderbird
Reading package lists... Done
Building dependency tree
Reading state information... Done
Note, selecting 'icedove' instead of 'thunderbird'
icedove is already the newest version (1:52.9.1+build3-0ubuntu0.16.04.1+8.0trisquel1).

So my question - is there more secure to install Thunderbird mail client over current Icedove in Trisquel8? And how one does install Thunderbird?

Thank you